Interannual Variation of Modified Circumpolar Deep Water in the Dotson?Getz Trough, West Antarctica

Widespread ice shelf thinning has been recorded in the Amundsen Sea recent decades, driven by basal melting and intrusions of relatively warm Circumpolar Deep Water (CDW) onto continental shelf. The Dotson Ice Shelf (DIS) is located to south polynya, a high rate because modified CDW (mCDW) fills Dotson-Getz Trough (DGT) reaches base Here, hydrographic data DGT obtained during seven oceanographic surveys from 2007 2018 were used study interannual variation mCDW volume properties their causes. Although showed weak variations at break, these intensified southward reached maximum front DIS. There, was ?8,000 km3 2007, rapidly decreased 4,700 2014 before rebounding 7,300 2018. We find that such variability coherent with local Ekman pumping integrated along modulated presence sea ice, complementing earlier theories involving break winds only. strength dominant south-southeast coastal wind modulates amplitude upwelling eastern boundary polynya austral summers surveyed years, apparently leading change DGT. note strong correlation between longitudinal location Low.